The present invention relates to a sidewall of a semi-trailer having a high baserail. More specifically, the present invention relates to a sidewall of a semi-trailer having a high baserail where the sidewall is formed of a plurality of composite side panels.
A semi-trailer 20 of the prior art is shown in FIG. 1. The semi-trailer 20 can be connected to a tractor (not shown) by conventional means, such as a fifth wheel assembly (not shown). The semi-trailer 20 includes a body 22 formed from a pair of rectangular sidewalls 24, a front wall 26, rear doors 28, a top panel or roof 30, and a bottom panel or floor 32. The floor 32 is supported by a conventional rear undercarriage assembly 34 and has a landing gear 36 secured thereunder. The roof 30 and an upper portion of the sidewalls 24 are secured to a top rail 38. The floor 32 and a lower portion of the sidewalls 24 are secured to a bottom rail 40.
Each sidewall 24 includes a plurality of vertical upstanding composite side panels 42 joined together by a joint configuration 44, preferably of the type disclosed in any one of U.S. Pat. Nos. 4,958,472, 5,860,693, 5,997,076, 6,220,651 and 6,412,854, all of which are owned by the assignee of the present application. Each composite side panel 42 includes a plastic core member 46 sandwiched between an inner thin metal skin 48 and an outer thin metal skin 50 bonded thereto by a suitable known adhesive or other like means.
The inner skin 48 and the outer skin 50 are preferably approximately 0.026 inches thick. The skins 48, 50 are preferably made of aluminum; galvanized, full hardened steel, such as AISI Grade E full hard steel because of its cost effectiveness, or the like. Preferably, the outer skin 50 is made of ASTM G90 galvanized steel and the inner skin 48 is made of ASTM G60 galvanized steel. Aluminum may be used, but it may be tool soft for some purposes and strength and punch resistance are sacrificed, however, aluminum is lightweight. Typically, each composite side panel 42 is four feet in width, but can be longer or shorter depending on the application.
Each core member 46 is made of some type of compressible non-metal material, preferably thermoplastic, such as polypropylene or high density polyethylene. These materials are relatively inexpensive as compared to aluminum found in prior semi-trailer wall constructions. In addition, because a composite side panel 42 is used, the weight of the semi-trailer construction is reduced over semi-trailers having aluminum sidewalls.
The semi-trailer 20 having sidewalls 24 formed of composite side panels 42 typically rests on the bottom rail 40 such that the outer skin 50 extends all the way down to the bottom rail 40. The bottom rail 40 also typically has a vertical section 47 which is about six (6) inches high, against which the inner skin 50 of the composite side panels 42 abuts against, as illustrated in FIG. 2. A scuff plate 49 is also positioned against the inner skin 50 of the composite side panels 42 and is positioned above the vertical section 47 of the bottom rail 40. The composite side panels 42 are secured to both the vertical section 47 of the bottom rail 40 and to the scuff plate 49 by rivets 51. The vertical section 47 and the scuff plate 49 typically run the entire length of the sidewall 24 of the semi-trailer 20 from the front wall 26 to the rear doors 28. The scuff plate 49 is provided to protect the composite side panels 42 from damage by contact with goods and/or loading equipment such as a fork lift truck.
While the use of semi-trailers 20 having sidewalls 24 formed of composite side panels 42 has been met with much praise in the industry because they are both lightweight and strong, these semi-trailers do have some disadvantages associated therewith.
For example, the outer surface of the composite side panels 42 are susceptible to damage proximate to the bottom rail 40 caused from sideswipes by other semi-trailers, typically during docking. Also, if the composite side panels 42 are damaged either by sideswipes or by a forklift, such that replacement thereof is necessary, the construction of the sidewalls 24 does not allow for the easy replacement thereof or easy repair thereof.
Thus, there is a need for a sidewall construction for a semi-trailer using composite side panels which overcomes the aforementioned disadvantages. The present invention provides such a sidewall construction for a semi-trailer using composite side panels.